1. Field of the Invention
The invention relates to an encryption processing apparatus which performs data encryption on received data, stores the resulting encrypted data in a storage apparatus, and then outputs it from the storage apparatus, and to an encryption processing system
2. Description of the Related Art
Recently, there is known such a system that data which is sent out from a host apparatus such as a server, is temporarily stored in a storage apparatus such as a memory and hard disk drives, and thereafter the data is outputted from the storage apparatus.
One of typical examples of such systems is a printing system provided with a storage apparatus in which system, even when many users share a printer of the printing system and simultaneously send out data thereto, printing of the data is carried out in such a manner that the data is temporarily stored in the storage apparatus and is sequentially outputted from the storage apparatus to the printer.
According to the system, however, if data remains stored in the storage apparatus after being outputted from the storage apparatus, it is permitted to output the data from the storage apparatus again. It is therefore in general carried out to erase the storage data from the storage apparatus after the output of the data to the printer. This processing is very effective in cases where the data is of confidential information.
In this technique, however, at least for a certain period before the data sent out from the host apparatus is outputted to the printer after being temporarily stored in the storage apparatus, the data remains to be stored in the storage apparatus. Therefore, there is a possibility that the data is read out by a third party during the period or the storage apparatus in which the data is stored is stolen. Accordingly, it is hard to say that the security of the data is ensured.
Then, in Japanese Unexamined Patent publication JP-A 4-3660 (1992), the following technique is disclosed that received data is encrypted and stored in the storage apparatus of the facsimile, and when outputting the data, a user who is permitted to handle the stored data inserts an IC card for decrypting the data into the storage apparatus, to output decrypted data.
However, the above-mentioned technique, since all the received data is encrypted in the storage apparatus, has an inconvenience that much time is spent in the encryption processing because of burdening the storage apparatus with the processing, or data with no need for the encryption is also encrypted. Further, it has another inconvenience that the IC card should be inserted when decrypting the data.